Technical Data
43
Power Meter, SIMEAS P 7KG7750/55, Manual
E50417-B1076-C375-A3, Release 01.2009
4.2 Hardware Interface
Bus connection 9-pole D-SUB outlet
Table 4-1 Pin assignment of the bus connector (D-SUB outlet)
Protocol semi-duplex
Max. line length 1000 m / 3300 ft.
Insulation level AC 500 V
Bus termination Bus termination via bus plug with integrated terminating resistors.
Figure 4-1 Recommended external termination circuit with open-line fail-safe
Pin Signal Meaning
1 Shield Shield / Operational ground
2--
3 A RS485 connection pin A
4 RTS Directions control
5GND
EXT
Data transmission level (ground towards +5 V
EXT
)
6+5 V
EXT
Supply voltage for terminating resistors (DC +5 V, max. 100 mA)
7--
8 B RS485 connection pin B
9--
390 Ohm
220 Ohm
390 Ohm
A
B
+5 V
EXT
GND
EXT